1. Field of the Invention
The present invention relates to a voltage application structure used for a display of a television receiver, a computer, or the like, a message board that displays characters or images, or the like. The present invention also relates to a display apparatus using this voltage application structure.
2. Related Background Art
In recent years, there have widely been used color cathode-ray tubes (CRTs) as display apparatuses. The driving principle of these CRTs is a method with which electron beams from cathodes are deflected to have phosphors of screens emit light. This means that the display apparatuses are required to have depths corresponding to their screen sizes.
However, in the case where the depths of the display apparatuses are increased, there occur problems such as enlarged installation spaces and increased weights thereof, which has led to a strong and earnest desire to realize a flat type display apparatus whose thickness and weight are reduced.
As examples of the flat type display apparatus and a method of supplying power of a high voltage to the apparatus, there is disclosed a surface conduction electron-emitting type display panel (hereinafter referred to as the xe2x80x9cSEDxe2x80x9d) in JP 10-321167 A and JP 2000-195449 A and there is also disclosed a field emission type display apparatus (hereinafter referred to as the xe2x80x9cFEDxe2x80x9d) in JP 05-114372 A.
In FIG. 10, there is shown the outline of the FED disclosed in JP 05-114372 A as a conventional flat type display apparatus.
We have found, as a result of earnest studies, a problem that it is difficult to perform the control of an area to which an anode potential is applied, in the case where a potential is supplied to an anode electrode through an elastic body like in JP 2000-195449 A and JP 05-114372 A described above. This point will be described in detail below. In the case where a potential is supplied to an anode electrode through an elastic body in the manner described above, each panel has a different distance between a rear plate and a face plate or the elastic characteristic of an elastic body is degraded as a result of a process like seal bonding that is performed at high temperature. As a result, there is a case where each panel has a different shrinking state of the elastic body or a different length of elapsed time results in a different shrinking state. In such a case, there is varied an area within a panel in which the elastic body exists, which results in a situation where there is changed an application area in which an anode potential is applied to the elastic body. This changing of the application area of the anode potential causes various problems such as (1) changing of the trajectory of an electron beam emitted from an electron-emitting device in the vicinity of the anode potential application area and (2) induction of accidental discharging within a panel.
We also have found that a high-voltage terminal for supplying a potential to an anode electrode of an anode substrate is led to the outside using an opening established in a cathode substrate, so that a potential on a surface (surface of the cathode substrate exposed to the air) on a side opposite to a surface forming a vacuum container of the cathode substrate becomes unstable and this may bring about accidental discharging or the like. This point will be described in detail below. In the case where a high-voltage terminal for supplying a potential to an anode electrode of an anode substrate is led to the outside through an opening established in a cathode substrate in the manner described above, the periphery of the opening on a surface of the cathode substrate on the atmosphere side is covered with the potential of the high-voltage terminal, so that the periphery is regulated to have a potential that is approximately the same as that of the high-voltage terminal. The atmosphere on the periphery of the opening on the surface of the cathode substrate on the atmosphere side is the air, so that there is a fear that discharging occurs under such a state where a high voltage is applied. In particular, in the case of a flat panel display, a drive circuit of a display apparatus, a vacuum container holding structure that connects a vacuum container to an enclosure, and the like are arranged adjacent to each other around the surface on a side opposite to the vacuum container forming surface of a cathode substrate, so that there is a fear that accidental discharging is induced between the high-voltage terminal and another member.
Also, there is another problem described below in the case of a structure shown in FIG. 10 described above.
The vacuum sealing of a seal body 18 requires the vacuum sealing at an interface between a terminal leading portion 17 and the seal body 18 and the vacuum sealing between the seal body 18 and a rear panel 3. As a result, there is an increased possibility of leakage because a plurality of sealed portions exist, which makes it impossible to obtain a voltage application structure with high hermetic reliability.
Also, the terminal leading portion 17 protrudes to the outside, which becomes a great hindrance to the reduction in the size and thickness of an ultra thin flat panel display apparatus 20.
Further, during a process of producing the ultra thin flat panel display apparatus 20, in order to cope with the protrusion of the terminal leading portion 17 to the outside, it is required to secure a space for a production apparatus and an inspection apparatus. As a result, the process of producing the display apparatus becomes complicated and the costs rise.
In view of the problems described above, an object of the present invention is therefore to suppress the induction of accidental discharging by controlling an area to which a high voltage is applied, to reduce the size, thickness, and costs of a display apparatus, and to provide a display apparatus where a potential is stabilized.
In order to achieve the above-mentioned object, according to the present invention, there is provided a display apparatus comprising at least: a vacuum container that includes at least a first substrate and a second substrate, the first substrate having on the same surface an electron source and a first conductor that is regulated to have a higher potential than the electron source, and the second substrate having on a surface thereof an image forming member that has a second conductor regulated to have approximately the same potential as the first conductor, with the surface having the image forming member being arranged so as to oppose the surface of the first substrate having the electron source; and a conductive elastic structure made at least partially of an elastic body, which exists inside of the vacuum container and contacts the first conductor and the second conductor so as to electrically connect the first conductor to the second conductor, the display apparatus being characterized in that conductive elastic structure is contained within an area in which an orthographic projection area of the first conductor to the second substrate overlaps an orthographic projection area of the second conductor to the first substrate.
Also, preferably, the display apparatus is characterized in that the first substrate has a through hole terminal connected to the inside of the vacuum container and the potential of the first conductor is regulated through the through hole terminal.
Also the display apparatus is characterized in that the first substrate has low-voltage wiring that is arranged around the first conductor and is regulated to have a lower potential than the first conductor.
Also, the display apparatus is characterized in that a high-resistance film is provided between the first conductor and the low-voltage wiring.
Also, the display apparatus is characterized in that each of the first conductor and the conductive elastic structure is axially symmetrical about a center axis, and the respective center axes of the first conductor and the conductive elastic structure substantially coincide with each other.
Also, the display apparatus is characterized in that means for sealing the vacuum container also serves as means for positioning the conductive elastic structure.
Also, the display apparatus is characterized in that the conductive elastic structure has an elastic portion including a plurality of springs whose number is at least equal to three.
Also, according to another aspect of the present invention, there is provided a display apparatus comprising at least: a vacuum container that includes at least a first substrate having an electron source on a surface thereof and a second substrate having on a surface thereof an image forming member arranged such that the surface having the image forming member opposes the surface of the first substrate having the electron source, the image forming member having an anode electrode that is regulated to have a higher potential than the electron source; and a conductive member that exists inside of the vacuum container, is electrically connected to the anode electrode, and is led to the outside of the vacuum container through a hole established in the first substrate, the display apparatus being characterized in that a conductive layer is provided around the hole on a surface of the first substrate on a side opposite to the inner surface of the vacuum container; and the conductive layer is regulated to have a lower potential than the anode electrode.
Also, preferably, the display apparatus is characterized by comprising a circuit for driving the display apparatus in the vicinity of the first substrate at the outside of the vacuum container.
Also, the display apparatus is characterized by further comprising a voltage withstand structure between the conductive member and the conductive layer.
Also, the display apparatus is characterized in that the voltage withstand structure is constructed from an insulating material.
Also, the display apparatus is characterized in that the voltage withstand structure is constructed from a high-resistance film.